Predictive Factors for Local Recurrence after Intraoperative Microwave Ablation for Colorectal Liver Metastases

How Can We Improve the Survival of Patients with Colorectal Liver Metastases Using Thermal Ablation?

Thermal ablation has been widely used for patients with small colorectal liver metastases (CRLMs), even for resectable cases; however, solid evidence has been scarce. (1) Thermal ablation versus liver resection. Some propensity-score matching studies using patients with balanced baseline characteristics have confirmed less invasiveness and the comparable survival benefits of thermal ablation to liver resection. A more recent pivotal randomized controlled trial comparing thermal ablation and liver resection was presented during the American Society of Clinical Oncology 2024 meeting. Diameter ≤ 3 cm, ten or fewer resectable and ablatable CRLMs were assigned to thermal ablation or liver resection. No differences were observed in the overall survival and local and distant progression-free survival with less morbidity. (2) Combination of thermal ablation and liver resection. Four matching studies demonstrated comparable data between the combination and liver resection alone groups in the long-term survival and recurrence rates without increasing the postoperative complication rates. The selection of the two approaches depends primarily on the number, size, and location of the CRLMs. (3) Chemotherapy in combination with thermal ablation. A propensity-score matching study comparing thermal ablation ± neoadjuvant chemotherapy was conducted. The addition of neoadjuvant chemotherapy was an independent predictive factor for good progression-free survival without increasing morbidity. Two randomized controlled trials demonstrated that additional thermal ablation to systemic chemotherapy can improve the overall survival for initially unresectable CRLMs. (4) Conclusions. Thermal ablation can provide survival benefits for patients with CRLMs in various situations, keeping adequate indications.

Microwave ablation for colorectal liver metastases with ultrasound fusion imaging assistance: a stratified analysis study based on tumor size and location

PURPOSE

To investigate the efficacy of ultrasound fusion imaging-assisted microwave ablation (MWA) for patients with colorectal liver metastases (CRLM) based on stratified analysis of tumor size and location.

METHODS

Patients with CRLM who underwent ultrasound fusion imaging-assisted MWA in our hospital between February 2020 and February 2023 were enrolled into this retrospective study. Ultrasound fusion imaging was used for detection, guidance, monitoring and immediate evaluation throughout the MWA procedures. Technical success, technique efficacy, local tumor progression (LTP), intrahepatic progression and overall survival (OS) were recorded and analyzed. The subgroup analysis of intrahepatic progression of MWA for CRLM was performed according to tumor size and location.

RESULTS

A total of 51 patients with 122 nodules were enrolled. Both technical success and technique efficacy were acquired in all nodules. In a median follow-up period of 19 months, 2.5% of the nodules (3/122) were observed LTP. The 1-year and 2-year cumulative intrahepatic progression rates were 38.7% and 52.1% respectively. Patients were divided into subgroups according to tumor size (≥ 30 mm, n = 13; < 30 mm, n = 38) and tumor location (perivascular, n = 20; non-perivascular, n = 31 and subcapsular, n = 36; non-subcapsular, n = 15). The cumulative intrahepatic progression rates were similar between the subgroups regarding tumor size and perivascular location, while significantly higher in the subcapsular group than in the non-subcapsular group (p = 0.021).

CONCLUSION

Ultrasound fusion imaging-assisted MWA exhibited satisfactory local efficacy for CRLM, especially for non-subcapsular tumors.

Feasibility and safety study of ultrasound-guided percutaneous microwave ablation for sub-cardiac liver cancers without artificial ascites assistance

OBJECTIVES

To investigate the efficacy and safety of ultrasound (US)-guided microwave ablation (MWA) without artificial ascites (AA) inpatients with sub-cardiac (SC) liver cancers.

METHODS

This retrospective study included patients with the left lobe and caudate lobe of the liver cancer who underwent US-guided MWA in our institute from January 2020 to December 2022. According to whether the target lesion was located ≤5 mm from the pericardium, patients were divided into the SC group and the non-sub-cardiac (NSC) group. In the SC group, AA was not employed during the ablation procedure. The results of technical success, technical efficiency, local tumour progression (LTP), and major complications were recorded.

RESULTS

A total of 79 patients with 87 lesions were enrolled. There were 38 patients with 38 lesions in the SC group and 41 patients with 49 lesions in the NSC group. The median follow-up of all patients was 15 (range, 3-44) months. There was no significant difference in technical success rates (100% vs 100%), technique efficiency rates (100% vs 95.7%), LTP rates (2.63% vs 0%,), and major complication rates (2.63% vs 7.32%) between the SC group and the NSC group (P > .05). No cardiac-related complications occurred.

CONCLUSIONS

US-guided MWA without AA for SC liver cancers was safe and effective.

ADVANCES IN KNOWLEDGE

The clinical prognosis of thermal ablation without AA in the treatment of SC liver cancers is still unclear. The finding of this study provided evidence supporting the efficacy and safety of US-guided MWA without AA for treating this tricky location.

Cryoablation in the liver: how accurately does the iceball predict the ablation zone?

PURPOSE

To evaluate the accuracy with which the iceball predicts the realized ablation zone in patients undergoing cryoablation of the liver.

MATERIALS AND METHODS

Continuous patients who underwent cryoablation of primary or secondary malignancies of the liver were retrospectively reviewed. Iceball and ablation zone dimensions on 1 month follow up imaging were collected in three orientations, the long axis (LA), perpendicular transverse (PTR), and perpendicular craniocaudal (PCC). Factors which may predict differences in the measurements were evaluated with regression analysis. Oncologic outcomes were also collected.

RESULTS

The mean size of the iceball was 5.5 ± 1.1 cm, 3.9 ± 1.1 cm, and 4.4 ± 1.4 cm in the LA, PTR, and PCC orientations, respectively. The mean size of the one-month ablation cavity was 4.3 ± 1.3 cm, 3 ± 1.1 cm, and 3 ± 1.3 cm in the LA, PTR, and PCC orientations, respectively. The iceball was significantly larger than the ablation zone in all orientations (p < 0.001). When comparing HCC and non-HCC patients the Kaplan-Meier analysis of TTLP, the Kaplan Meier curves deviated significantly (p = 0.015, HR 2.26 (95%CI 1.17-4.37)). When a similar analysis was performed looking at TTP again the curves diverged significantly (p = 0.002, HR 2.4 (95%CI 1.37-4.19)).

CONCLUSION

The iceball seems to overestimate the realized ablation zone by about 1 cm in all orientations during hepatic cryoablation.

Percutaneous image-guided ablation for hepatic metastases

The presence of hepatic metastases indicates advanced disease and is associated with significant morbidity and mortality, especially when the hepatic disease is not amenable to locoregional treatments. The primary tumour of origin, the distribution and extent of metastatic disease, the underlying liver reserve, the patient performance status and the presence of comorbidities are factors that determine whether a patient will benefit from hepatectomy or local curative-intent treatments. For patients with metastatic colorectal cancer, the most common primary cancer that spreads to the liver, several studies have demonstrated a survival benefit for patients who can be treated with hepatectomy and/or percutaneous ablation, compared to those treated with chemotherapy alone. Despite advances in surgical techniques increasing the percentage of patients eligible for surgery, most patients have unresectable disease or are poor surgical candidates. Percutaneous ablation can be used to provide local disease control and prolong survival for both surgical and non-surgical candidates. This is typically offered to patients with small hepatic metastases that can be ablated with optimal (≥10 mm) or at least adequate minimum ablation margins (≥5 mm), as high local tumour control rates can be achieved for these patients which are comparable to surgical resection. This review summarizes available evidence and outcomes following percutaneous ablation of the most frequently encountered types of hepatic metastases in the clinical practice of interventional oncology. Patient selection, technical considerations, follow-up protocols and oncologic outcomes are presented and discussed.

A Review of Resection and Surgical Ablation for Primary and Secondary Liver Cancers

The surgical management of primary and secondary liver tumors is constantly evolving. Patient selection, particularly with regard to determining resectability, is vital to the success of programs directed toward invasive treatments of liver tumors. Particular attention should be paid toward determining whether patients are best served with surgical resection or ablative therapies. A multidisciplinary approach is necessary to provide optimal care to patients with liver malignancy.